How would you explain the reflection of light to a layman? Since, θ 1 = θ 2 as per the law of reflection. A ray of light strikes a surface at an angle of 70° to the normal. Where θ 1 and θ 2 represent the angles of incidence and reflection respectively. Why so? This is because the light emitted from the candle falls onto the objects and then bounces back to your eyes to let you see them.
![finding angle of reflection finding angle of reflection](https://hi-static.z-dn.net/files/d98/4bf9c454f343d8ec4695e8e66062187e.jpg)
This way of using thin converging lens which project parallel light rays must be in a spot lightwhich project parallel light rays for very long distances (image is formed at infinity). Object distance is at F: Image formed at infinity (light rays travel parallel to each other after passing through lens).
![finding angle of reflection finding angle of reflection](https://haygot.s3.amazonaws.com/questions/897926_512229_ans_6005157270d1489ca4dc8feddf2b643d.png)
Since object is at infinity, this way of using thin converging lens must be in a telescope for viewing distant object. Object distance is at infinity: Image formed is real and at F. This way of using thin converging lens is in a photocopier. Object distance at 2F: Image formed is inverted, real and same size as object. Just have to try out and make mistakes and relearn the correct way of doing things to master the thing one is learning. The best way is still to draw out your own ray diagram to figure out what type of image is formed and then guess the use of the lens using common sense.
![finding angle of reflection finding angle of reflection](https://i.ytimg.com/vi/yjZQfUpFnbc/maxresdefault.jpg)
You may refer to your own school notes, textbooks or assessment books for these other examples. Take refractive index of water n be 1.33.Īns: Applying the formula sin C = 1/ n, we will substitute the value of n to be 1.33 and just solve the formula to find angle C, the critical angle. This is basically what the question in this video is talking about.
![finding angle of reflection finding angle of reflection](https://image3.slideserve.com/7066559/total-internal-reflection-tir5-l.jpg)
Qn asked: Find the critical angle for light travelling in the water. I provide another simple way to appreciate the question asked in this video if you find the question asked on finding critical angle a bit confusing. The refractive index of water n in this video is 1.33 being substituted into the formula for finding critical angle. If you got a little bit confused over the beginning part about applying refractive index of the two media using Snell's Law, just ignore that part and look at the last few steps which resembles sin C = 1 / n. The calculation shown in this video is using this formula sin C = 1 / n for finding critical angle. C is critical angle and n is the refractive index of denser medium. When light is travelling at angle of incidence greater than critical angle, total internal reflection occurs. This video explores critical angle, total internal reflection and formula sin C = 1/ n.ĭo take note that total internal reflection can have a possibility of happening ONLY when light is travelling from a denser medium to a less dense medium (for O level the less dense medium is always given as air).Ĭritical angle is the angle of incidence of light travelling in the denser medium in order to have an angle of refraction of 90˚ in the less dense medium.